The first part of the small intestine is called the duodenum. It is where most of the food is broken down by enzymes. Further on, the small intestine absorbs useful compounds from the digested food. It does this through small villi or tiny microvilli.[1] These are very small, hair-like structures in the walls of the intestine.

The large intestine is also called the bowel. It absorbs water, and any nutrients still remaining. It also absorbs vitamins made by the gut flora in the colon. Finally it expels waste through the anus.[2]